Signal lamp with built-in ground strap

ABSTRACT

THE HOUSING OF A SIGNAL LAMP IS FABRICATED OF AN ELECTRICAL INSULATOR, AND A THREADED STEM DEPENDS FROM THE HOUSING FOR MOUNTING THE LAMP ON A SUPPORT, A GROUND STRAP IS ELECTRICALLY CONNECTED TO ONE OF THE CONTACTS OF A BULB SOCKET IN THE HOUSING AND HAS A PART THEREOF POSITIONED IN AN OPEN CHANNEL IN THE STEM SUCH THAT THIS PART IS CONTACTED BY AN ELECTRICALLY CONDUCTIVE NUT ADAPTED TO BE THREADED ON THE STEM WHEN MOUNTING THE LAMP IN POSITION.

Feb. 16, 1971 v H. MAG! 3,564,483

SIGNAL LAMP WITHQfBUILT-IN GROUND S'I'RAP Filed March 21, 1969 33INVENTOR.

Attorney 7 United States Patent 3,564,483 SIGNAL LAMP WITH BUILT-INGROUND STRAP Hugo Magi, Etobicoke, Ontario, Canada, assignor to DominionAuto Accessories Limited, Toronto, Ontario, Canada Filed Mar. 21, 1969,Ser. No. 809,315 Int. Cl. H01r 13/32 US. Cl. 339-130 7 Claims ABSTRACTOF THE DISCLOSURE The housing of a signal lamp is fabricated of anelectrical insulator, and a threaded stem depends from the housing formounting the lamp on a support. A ground strap is electrically connectedto one of the contacts of a bulb socket in the housing and has a partthereof positioned in an open channel in the stem such that this part iscontacted by an electrically conductive nut adapted to be threaded onthe stem when mounting the lamp in position.

This invention relates generally to lamps, and, more particularly, tosignal lamps, such as direction signal lamps, for motor vehicles.

The grounding of a lamp having a hOusing fabricated of an electricallyconductive material generally does not pose much of a problem, since thehousing itself can serve as a vehicle for grounding the lamp. Thiscannot be done, however, when the housing is fabricated of anelectrically insulating material such as plastic, for example, and ithas been common practise in such cases to provide a grounding wire thatis brought out of the lamp and grounded in some way.

In accordance with the instant invention there is provided a lamp thathas a permanent ground strap so ranged that securing of the lamp to agrounded support automatically will ground the lamp.

This invention will become more apparent from the following detaileddisclosure, taken in conjunction with the appended drawings, in which:

FIG. 1 is a perspective exploded view f part Of a direction signal lampembodying the instant invention; and

FIG. 2 is a front elevation, partly broken away and partly in section,showing how a lamp embodying the instant invention is mounted.

Referring to the drawings, a direction signal lamp includes a housing 10made of electrically insulating material, e.g., a suitable plastic, towhich is fastened by any suitable means lenses 11. Only one lens 11 isshown, but it will be understood that an identical lens will projectforwardly from the front of housing 10 being mounted on the rim 12thereof. Lenses 11 are transparent or translucent and may be coloured orplain. Generally one lens will be red and the other amber for adirection signal lamp. Lenses 11 may have semicircular flanges thereonthat snap into mating grooves in rims 12, or O-rings may be employedbetween lenses 11 and rims 12.

Projecting inwardly from rim 12 but formed integral therewith andconstituting a part of housing 10 is a strengthening partition 13 inwhich is provided a recess 14 that is occupied by the light bulb (notshown) of the lamp.

Located below recess 14 and held in position by shock absorbing andvibration dampening supports 15 that are described and claimed incopending patent application Ser. No. 32,084, filed Apr. 27, 1970 forShock Resistant Mountings for Light Bulbs and which are formed integralwith partition 13 is a light bulb socket 16. Part 16a of socket 16 isformed integral with the supports 15 and thus "ice is fabricated ofplastic, if this is the material used for housing 10. The other part 16bof socket 16 constitutes one contact for one terminal of the light bulbof the lamp and is made of metal. As may be seen by reference to thedrawings, socket 16 is of the bayonet type, but obviously could be ofthe type to receive a screw-in bulb. The other contact 17 of socket 16is conventional being an electrical contact disposed in or on a disc 18of electrically insulating material that is biased upwardly by a spring19.

Formed integral with housing 10 and depending downwardly therefrom is ahollow, threaded stem or stud 20. Stud 20 has an open channel 21 formedtherein. Located in channel 21 is a metal ground strap 22 that iselectrically connected to socket part 16b and the other end of which ishooked over the end of stud 20.

In the manufacture of the lamp shown in the drawings, the hooked end ofground strap 22 is inserted through an opening 23 in housing 10 thatregisters with channel 21, strap 22 is positioned in the channel, andthe hooked end of the ground strap is hooked over the end of stud 20.The rectangular end portion 24 of ground stra 22 then is positioned in arecess 25 formed for it in socket part 16a with the stud 26 extendingthrough the opening 27 formed in end portion 24, stud 26 being formedintegral with socket part 16a. Socket part 16b then is mounted on socketpart 16a with the studs 26 and 28 of socket part 1611 projecting throughopenings 29 and 30 formed in cars 31 and 32 of socket part 16b. Afterthis has been done, socket part 16b and ground strap 22 are physicallysecured together and positively electrically connected, as by ultrasonicwelding. When this has been accomplished, studs 26 and 28 are meltedover cars 31 and 32 to form caps that hold socket part 16b in place. Ofcourse, during the assembly of socket 16, spring 19, contact 17 and disc18 are located within the socket and the insulated conductor 33 that issoldered or otherwise connected to contact 17 is passed through opening34 in housing 10 and brought out of the lamp via hollow stem 20.

As best shown in FIG. 2, the depth of channel 21 preferably is such thatthe two edges 35 and 36 (FIG. 1) of ground strap 22 extend above theroots of the threads on stem 20. This ensures positive grounding of thelamp. In this regard, as best seen in FIG. 2, reference numeral 37designates a grounded part, say the fender, of a motor vehicle. Inmounting the lamp on the fender, stem 20 is inserted through an openingin the fender, an electrically conductive washer 38 is placed over stem20 and an electrically conductive nut 39 is screwed into stem 20 andtightened. The threads on nut 39 will bite into edges 35 and 36 ofground strap 22 and, when the nut has been tightened, grounding of thelamp will be effected automatically via ground strap 22, nut 39, washer38 and fender 37.

What I claim as my invention is:

1. A signal lamp comprising a housing fabricated of an electricallyinsulated material, a threaded stem depending from said housing formounting said lamp on a support, said stem having an Open channel formedtherein, an electrically conductive nut threadably engageable with saidstem, a light bulb socket disposed within said housing and having firstand second electrical contacts adapted to engage first and secondterminals of a light bulb when said light bulb is positioned in saidsocket, and a ground strap electrically connected to one of saidcontacts and having a part thereof positioned in said channel to becontacted by said nut when said nut is threaded on said stem.

2. A signal lamp according to claim 1 wherein said stem is formedintegral with said housing and also is fabricated of said electricallyinsulating material.

3. A signal lamp according to claim 2 wherein said stem is hollow andfurther including a wire electrically connected to the other of saidcontacts and extending out of said housing through said stem.

4. A signal lamp according to claim 1 wherein at least a portion of saidpart of said ground strap extends above the roots of the threads on saidstem.

5. A signal lamp according to claim 1 wherein the end of said groundstrap remote from said one contact is hooked over the end of said stem.

6. A signal lamp according to claim 3 wherein at least a portion of saidpart of said ground strap extends above the roots of the threads on saidstem.

7. A signal lamp according to claim 6 wherein the end of said groundstrap'remote from said one contact is 15 hooked over the end of saidstem.

References Cited UNITED STATES PATENTS OTHER REFERENCES IBM TechnicalDisclosure Bulletin, Self-locking 1O Terminal, M. C. Panaro, vol. 3, N0.6, November'1960,

page 6.

RICHARD E. MOORE, Primary Examiner US. Cl. X.R.

